There is evidence that breastfeeding is protective against asthma in early childhood. Compared to the children who were not breastfed, those who were breastfed for at least 4 months had vital capacities that were larger than those who were not breastfed, after adjusting for birth weight, sex, and current height and weight (0.008). In addition to bioactive factors transferred to the infant in breast milk, another potential explanation for these associations is the mechanical stimulus due to prolonged suckling at the breast that results in improved mechanics of ventilation in breast fed children compared to bottle-fed infants.
Physical exercise training resulting from suckling at the breast, about six times daily on average (for more than four months), may result in increased elasticity and efficiency of the lung parenchyma. This may lead to increases in lung capacity and airflow in breastfed children compared to bottle-fed children. Such differentials in the pressure generated between breastfed and bottle fed infants have been noted by previous researchers, with findings of up to a three-fold higher negative pressure due to breastfeeding. Thus, at least some of the benefits of breastfeeding may he lost when mothers practice “indirect” breastfeeding (i.e. pumping and bottle feeding their infants) compared to direct suckling at the breast. When direct breastfeeding is not possible, the benefit conferred by direct suckling may be (partly) achieved by the use of modified feeding bottles that would mimic natural direct breastfeeding. However, conventional bottle designs seek to increase pressure and remove negative pressure from the bottle to make fluids flow more easily out of a bottle.
Thus, in order to promote normal lung growth and development, an artificial increase of flow “resistance” from infant feeding bottles may prove beneficial. Such bottles are of increasing significance to improve respiratory health, since approximately 75% of the mothers in the United States pump and bottle feed their children, in particular after one month of lactation.
As such, a need exists for devices that better replicate natural direct breastfeeding. Methods relating to such devices would also be desirable.